Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenues	$ 802.3	$ 674.2
Cost of sales	739.8	588.6
Gross profit	62.5	85.6
Selling, general and administrative expenses	50.6	52.9
Restructuring charges	0.9	0.4
(Gains) losses on derivative financial instruments	(33.9)	28.2
Other operating expense, net	0.7	1.0
Operating income	44.2	3.1
Interest expense, net	33.8	27.1
Other expense, net	0.4	0.5
Income (loss) before income taxes	10.0	(24.5)
Provision for income taxes	5.4	10.7
Net income (loss)	4.6	(35.2)
Comprehensive income (loss)	$ 25.1	$ (25.6)